Hydraulic fracturing or fracking is a technique applied to the extraction of natural gas or oil in unconventional deposits. It involves creating several channels with high permeability by means of high-pressure water injection, in order to overcome the resistance of the rock and to form a controlled fracture in the depth of the well.
How does hydraulic fracturing work?
With the technique of fracking, it is possible to exploit the gas or oil that is accumulated in the fissures and pores of stratified sedimentary rocks. These are fine or very fine grains (usually marls or slates) and have low permeability, which prevents the mobilization of gas to areas of easy extraction. To carry out hydraulic fracturing, hundreds of wells occupy large areas.
Millions of liters of water are injected into these wells, also composed of a chemical cocktail for extraction. This fluid rich in chemicals and sand facilitates the release of gas and flows into the mouth of the extraction orifice.
This procedure can be performed vertically or horizontally, which is the most common. New ways can be created and opened to continue exploring the subsoil to find new resources.
Where does fracking occur and why is it necessary?
To understand where fracking occurs and why it is necessary, it is important to differentiate between conventional and non-fracking deposits.
They are the traditional deposits of oil and gas. The hydrocarbons are found in rocks that serve as a warehouse and have a stratigraphic structure. The parent rock that contained a large amount of organic matter, high porosity and permeability produced the hydrocarbons from a process that included effects of pressure and temperature. Later, the hydrocarbons migrated through a channel, ending up trapped in a storage rock by the effect of a seal.
These deposits are different from the previous ones because the parent rock did not have permeability for the hydrocarbons to migrate. That is why, when the hydrocarbons were formed, they were concentrated in the parent rock. To be able to exploit them, artificial permeability must be stimulated, this process is what is called fracking or hydraulic fracturing.
Advantages of hydraulic fracturing
- The main advantage is that it allows access to gas and oil that can not be extracted using conventional methods.
- In some countries, the price of fuel has decreased thanks to the introduction of this method.
- It guarantees that there are reserves for up to 100 years.
Disadvantages of hydraulic fracturing
- Exaggerated amounts of water must be used, this raises the cost greatly.
- The chemical cocktail used is composed of contaminating elements with high carcinogenic percentages and may contaminate the waters of the subsoil.
- There are experts who assure that a disaster can happen if some procedure in the technique is carried out badly.
- Experts say that fracking may cause small earthquakes.
- Those who defend the environment consider that continuing with hydraulic fracturing contributes to the oblivion of renewable energies
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